Evaluation of biodegradability and oxidation degree of hospital wastewater using photo-Fenton process as the pretreatment method

In this work, the photo-Fenton process was used for the pretreatment of hospital wastewater with the objective of improving its overall biodegradability and determining the degree of increased oxidation. The chemical oxygen demand (COD), 5-day biochemical oxygen demand (BOD5), total organic carbon (TOC) and toxicity towards the gram negative marine bioluminescent bacteria of the species V. fischeri were selected as the environmental sum parameters to follow the performance of this process. The enhancement of biodegradability, evaluated in terms of the BOD5/COD ratio, increased from 0.3 to 0.52 and the oxidation degree, calculated in terms of AOS, leveled up from -1.14 to +1.58 at the optimum conditions; a dosage ratio of COD:H2O2:Fe(II) at 1:4:0.1, and a reaction pH of 3. The reduction in the inhibition percentage from the toxicity test indicated the safe levels for micro-organisms in degrading the residual organic substance in this method. Almost total removal percentages of COD, BOD5, and TOC were found by a sequential activated sludge process for the pre-treated wastewater. Results obtained from this work indicated that the photo-Fenton process could be a suitable pretreatment method in reducing toxicity of pollutants and enhancing biodegradability of hospital wastewaters treated in a coupled photochemical-biological system.     

Effect of partial substitution of wheat flour with resistant starch on physicochemical,sensorial and nutritional properties of breadsticks

This study determined the physicochemical, sensorial and nutritional properties of breadsticks to which a resistant starch (RS)-rich ingredient was incorporated by partial substitution, that is, 40%–70%, of hard wheat flour in the control recipe. Wheat flour substitution at the levels exceeding 50% lightened the colour while decreasing the moisture content and hardness of breadsticks, which was explainable by the microstructure. Changes in properties of breadsticks also affected the suitability of its sensory attributes, particularly colour and texture. Breadsticks, of which half of wheat flour was substituted, contained less protein and calories but higher carbohydrate than the control formula. Such flour substitution increased RS content closed to its effective dose of 15 g in a 45-g serving, which led to approximately 15% reduction in in vitro glycaemic index. Therefore, incorporating effective dose of RS in breadsticks could be performed, without causing substantial changes in product quality, by partial substitution of wheat flour.     

Effect of Heating and Homogenization on the Stability of Coconut Milk Emulsions

: The effects of homogenization and heat treatment on the colloidal stability of coconut milk were studied. Fresh coconut milk (15% to 17% fat, 1.5% to 2% protein) was extracted and stored at 30 °C before homogenization at 40/4 MPa (stage I/stage II). Both homogenized and non‐homogenized samples were heated at 50 °C, 60 °C, 70 °C, 80 °C, and 90 °C for 1 h. Homogenization reduced the size of the primary emulsion droplets from 10.9 to 3.0 μm, but increased the degree of flocculation, presumably via a bridging mechanism. This flocculation was also responsible for increased viscosity of the homogenized samples. Heating increased the degree of flocculation in both non‐homogenized and homogenized samples. A slight amount of coalescence was also observed after heating above 80 °C. All samples creamed after 24 h of storage, but the heated samples formed a larger cream layer, presumably because the flocculated droplets packed together less efficiently. Optical microscopy was used to confirm the combination of flocculation and creaming responsible for changes in coconut milk quality. The information obtained from this study provides a better understanding of the emulsion science important in controlling coconut milk functionality.     

A Bayesian Approach for Dynamic Variation of Specific Sectors in Stock Exchange: A Case Study of Stock Exchange Thailand (SET) Indexes

Wireless Personal Communications - This paper aims to investigate the identification of sectors of stock exchange that were positively or negatively driven by fundamental monetary tools. A Bayesian...     

Quality maintenance and economy with high-temperature paddy-drying processes

Drying processes result in some loss of product quality. Three drying systems for paddy were investigated for their effects on head-rice yield and whiteness. Fluidised-bed drying, tempering and ambient air ventilation units were the main components, but they were arranged differently in each drying system. Heat- and mass-transfer equations were applied to predict the change in moisture content for each drying system. Both the experiments and simulations indicated that the two sub-drying systems (system No. 2) with tempering and ventilation as elements of each stage yielded higher drying capacity and thermal efficiency than the single drying system (system No. 1), in which paddy was treated with the drying, tempering and ventilation units only once. The proportion of full kernels and value of the whiteness obtained from both drying systems were not significantly different. System No. 3, where grains after the first tempering were dried immediately by the second fluidised-bed dryer with no ventilation unit, produced poor head-rice yield and colour and was unacceptable for producing white rice.     

MANAGING MOIST PADDY BY DRYING, TEMPERING AND AMBIENT AIR VENTILATION

This paper describes a strategy for reducing moisture in paddy by fluidized bed drying, tempering and ambient air cooling. Experimental results showed that after the three processes, moisture content was reduced from 33 % to 16.5 % dry-basis within approximately 53 minutes. During the first process, a fluidized-bed dryer was used to reduce the moisture content of paddy down to 19.5 % dry-basis within 3 minutes. Then the paddy was tempered for 30 minutes. Finally, it was cooled by ambient air (temperature and relative humidity of 30 °C and 55-60% respectively) with air velocity of 0.15 m/s for 20 minutes. Quality of paddy in terms of head rice yield and whiteness was acceptable.     

Thin layer solar drying characteristics of silkworm pupae

Thin layer solar drying experiments of silkworm pupae using a solar tunnel dryer were conducted under the tropical weather conditions of Mahasarakham, Thailand. The dryer consisted of a transparent glass covered flat-plate collector and a drying tunnel connected in series to supply hot air directly into the drying tunnel using a blower. During the experiments, silkworm pupae were dried to the final moisture content of 0.15 kg water kg^?1 dry matter from 4.37 kg water kg^?1 dry matter in 373 min at the corresponding air flow rate of 0.32 kg s^?1. Ten different thin layer drying models were compared according to their coefficient of determination to estimate drying curves. The Midilli–Kucuk model precisely represents the solar tunnel drying behavior with the coefficient of determination (R²) of 0.9982. The maximum drying rate and effective moisture diffusivity were 0.6723 kg water kg^?1 dry matter h^?1 and 2.7696 × 10^?10 m² s^?1, respectively, on the drying air flow rate of 0.32 kg s^?1. A quality assessment shows that the lipid content of the dried silkworm pupae was not affected by the solar tunnel dryer. A slight decrease of polyunsaturated fatty acid (PUFA) was observed.